Shared parallel digital-to-analog conversion
First Claim
1. A machine used for digital-to-analog conversion, comprising:
- a. a first counter which provides a first countb. a first analog reference source which provides a first analog reference signalc. a first digital number value to be converted to a first analog valued. means for causing said first count to change as a function of timee. means for causing said first analog reference signal to change as a function of timef. means for detecting when said first count reaches said first digital number valueg. means for recording the value of said first analog reference signal as said first analog value when said first count reaches said first digital number valuewhereby said first analog value is the converted value of said first digital number value.
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Abstract
A digital-to-analog converter in which a counter tracks the elapsed time since the beginning of a conversion cycle. Simultaneously, a reference analog signal such as a voltage ramp is generated. When the count reaches a stored digital number value, a sample-and-hold circuit is triggered and acquires the value of the reference analog signal. Multiple stored digital number values can be converted using multiple sample-and-hold and trigger circuits which share the counter and the reference analog signal. Such parallel digital-to-analog conversion is useful in many applications such as digital communications, image display, and shared parallel analog-to-digital conversion.
41 Citations
34 Claims
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1. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. a first analog reference source which provides a first analog reference signal c. a first digital number value to be converted to a first analog value d. means for causing said first count to change as a function of time e. means for causing said first analog reference signal to change as a function of time f. means for detecting when said first count reaches said first digital number value g. means for recording the value of said first analog reference signal as said first analog value when said first count reaches said first digital number value whereby said first analog value is the converted value of said first digital number value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. means for initializing said first count to a first digital number value c. a first analog reference source which provides a first analog reference signal d. means for causing said first count to change as a function of time e. means for causing said first analog reference signal to change as a function of time f. means for detecting when said first count reaches a first digital threshold value g. means for recording the value of said first analog reference signal as a said first analog value when said first count reaches said first digital threshold value whereby said first analog value is the converted value of said first digital number value. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A digital-to-analog converter comprising a first circuit element, wherein:
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a. said first circuit element is used in a first instance for a first conversion of a first digital number to a first analog value b. said first circuit element is used simultaneously in said first instance for a second conversion of a second digital number to a second analog value c. said first circuit element comprises a first parameter that varies with time during a conversion operation d. said first circuit element is a member of a set of circuit elements, said set of circuit elements consisting of a first counter and a first analog reference source whereby said first circuit element is effectively shared in said first conversion and in said second conversion, rather than used in said first instance for said first conversion and separately in a second instance for said second conversion, and whereby said first circuit element is not simply a constant reference signal. - View Dependent Claims (28, 29, 30, 31)
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32. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. means for initializing said first count to a first digital number value c. means for causing said first count to change as a function of time d. means for detecting when said first count reaches a first digital threshold value e. means for averaging the output of said means for detecting when said first count reaches said first digital threshold value whereby the output of said means for averaging is the converted value of said first digital number value. - View Dependent Claims (33, 34)
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Specification